JP2000290178A - Antitumor agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject agent having excellent antitumor activities, enough safety and little adverse effects by bringing the agent to contain a specific fatty acid having conjugate double bonds. SOLUTION: This antitumor agent contains a >=20C fatty acid having conjugate double bonds (e.g. conjugate arachidonic acid, conjugate eicosapentaenoic acid, conjugate docosahexaenoic acid, conjugate docosapentaenoic acid, etc.), an ester of the aforementioned fatty acid (preferably an ester, etc., of the aforementioned fatty acid with an alcohol such as a 1-10C alcohol, ethylene glycol, propylene glycol, glycerol and the like) or a metal salt (preferably a sodium salt, potassium salt, calcium salt, zinc salt, magnesium salt and the like). The aforesaid fatty acid preferably contains 40-70% of conjugate diene and 60-30 % of conjugate polyene equal to or more than triene within the all conjugate double bonds. The dose is 10-5000 mg of the aforesaid fatty acid per day in case of an adult (60 kg body weight).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an antitumor agent, particularly to an antitumor agent useful for treating various different types of cancer.

[0002]

2. Description of the Related Art In recent years,
Cancer mortality continues to increase, and much research is being done to develop suitable treatments for treating cancer and reducing symptoms. In the field of chemotherapy, antibiotics (such as adriamycin and carcinophilin), antimetabolites,
Alkylating agents, hormonal agents and the like have been found as effective antitumor agents for cancer cells. However, many of these antitumor agents not only attack cancer cells, but also act on normal cells, so when administered to patients in need of cancer treatment, vomiting, nausea, anorexia, hair loss, etc. There was a problem causing side effects.

[0003] On the other hand, although fatty acids have various physiological actions, some fatty acids have been found to have an inhibitory effect on cancer cells. In particular, n-6,
The activity possessed by the n-3 series unsaturated fatty acids has attracted attention (see “AA, EPA, DHA-Highly Unsaturated Fatty Acids”, edited by Hikaru Kayama, pp. 150-170, published by Kosei Seishaku, 1995). Fatty acids are constituents of fats and oils that are ingested daily, and their use as safer therapeutic agents for cancer has been proposed. In addition, fatty acids are expected to be used not only for the purpose of treating cancer but also as a preventive food for cancer. Recently, it has been reported that conjugated linoleic acid in which linoleic acid is alkali-conjugated has a cancer cell growth inhibitory effect (Anticancer Research, No. 15, pp. 1241-1246, 19).
95). The effect is believed to be based on the theory that conjugated linoleic acid has antioxidant activity and on the effect on eicosanoid metabolism, but details are unknown. Parinaric acid (18: 4,9-cis, 11-trans, 13-trans, 15-cis-octadecatetraenoic acid) has also been found to have antitumor activity (Cancer Research, No. 51, pp. 6025-6030, 1991), and the physiological effects of conjugated fatty acids having more carbon atoms and more double bonds have not yet been reported. In addition, fatty acids are expected as safer antitumor agents,
Its antitumor activity is not satisfactory as compared with conventional antitumor agents, and fatty acids having more effective antitumor activity are desired.

[0004] Accordingly, an object of the present invention is to provide an antitumor agent containing a fatty acid or a derivative thereof, which has excellent antitumor activity, is highly safe and has few side effects, as an active ingredient.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that conjugated long-chain highly unsaturated fatty acids have an excellent antitumor effect. did. The present invention has been made on the basis of the above-mentioned findings, and comprises a fatty acid having 20 or more carbon atoms having a conjugated double bond, or an ester or metal salt of the fatty acid or other pharmacologically acceptable forms as an active ingredient. And an antitumor agent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the antitumor agent of the present invention will be described in detail. As described above, the fatty acid as an active ingredient of the antitumor agent of the present invention is a fatty acid having a conjugated double bond and having 20 or more carbon atoms (hereinafter, referred to as a conjugated long-chain highly unsaturated fatty acid).
If the carbon number is outside the above range, excellent antitumor activity as intended by the present invention cannot be obtained.

[0007] Such conjugated long-chain highly unsaturated fatty acids include conjugated arachidonic acid, conjugated eicosapentaenoic acid,
Conjugated docosahexaenoic acid, conjugated long-chain highly unsaturated fatty acids such as conjugated docosapentaenoic acid, and conjugated long-chain highly unsaturated fatty acid compositions in which two or more of these conjugated long-chain highly unsaturated fatty acids are mixed, and the like. However, the present invention is not limited to this example.

[0008] The conjugated long-chain highly unsaturated fatty acid may be a fatty acid as it is, or may be in the form of an ester or a metal salt. As the ester of the conjugated long-chain highly unsaturated fatty acid, the conjugated long-chain highly unsaturated fatty acid,
And an ester with one or more alcohols selected from the group consisting of 10 alcohols, ethylene glycol, propylene glycol and glycerin. Further, examples of the metal salt of the conjugated long-chain highly unsaturated fatty acid include one or more metal salts selected from the group consisting of sodium salt, potassium salt, calcium salt, zinc salt and magnesium salt. .

Further, the conjugated long-chain highly unsaturated fatty acid is
In addition to the ester or metal salt forms described above, any other pharmacologically acceptable forms such as amides and phospholipids may be used.

The above-mentioned conjugated long-chain highly unsaturated fatty acid can be prepared by a conventional method, that is, by converting a long-chain highly unsaturated fatty acid, an ester thereof or a fat or oil containing the long-chain highly unsaturated fatty acid into an organic solvent represented by ethylene glycol. It is easily obtained by alkali conjugation. The conjugation ratio is controlled to 80% or more, preferably 90% or more by controlling the reaction conditions.
Particularly preferably, the content is 95% or more.

The conjugated long-chain highly unsaturated fatty acid is
It is preferable that all the conjugated double bonds contain 40 to 70% of a conjugated diene and 60 to 30% of a conjugated polyene equal to or more than a triene. More preferably, as a conjugated polyene of triene or more, a conjugated triene is 15 to 35%, a conjugated tetraene is 10 to 20%, and a conjugated polyene of 3 to 15% or more.
%.

A conjugated diene contained in all conjugated double bonds,
The content ratio of the conjugated triene and the like can be calculated by measuring the UV spectrum of the conjugated long-chain highly unsaturated fatty acid. That is, a 2,2,4-trimethylpentane solution (or a hexane, heptane, or cyclohexane solution) of a conjugated long-chain highly unsaturated fatty acid having a known concentration is placed in an absorption cell, and the solvent used for dissolution is used as a control, and 233, 26
2, 268, 274, 308, 315, 322 and 34
Measure the absorbance at 6 nm. From the obtained absorbance, a prescribed calculation formula (edited by the Japan Oil Chemists' Society, standard fat and oil analysis test method 2.4.3.
According to 1), the content ratio of conjugated dienoic acid, conjugated trienoic acid, conjugated tetraenoic acid, and conjugated pentaenoic acid is calculated.

[0013] The mechanism of action of the above-mentioned conjugated long-chain highly unsaturated fatty acids as an antitumor agent is unknown. However, the antitumor agent of the present invention containing the conjugated long-chain polyunsaturated fatty acid as an active ingredient exhibits an effective antitumor cell action against various tumors irrespective of the tissue, as shown in Examples below. Therefore,
By administering the antitumor agent of the present invention to tumor patients in various modes, it is expected that a very effective antitumor effect will be exhibited.

The form of the antitumor agent of the present invention comprising the above-mentioned conjugated long-chain highly unsaturated fatty acid, ester or metal salt of the fatty acid or other form as an active ingredient is not limited, and the administration method and application are not limited. Various forms such as injection solutions, suppositories, ointments, tablets, capsules, powders, granules, and drinks can be appropriately selected depending on the type, shape, location, and the like of the tumor to be treated. The antitumor agent of the present invention may contain pharmacologically acceptable diluents, stabilizers, excipients, and the like, depending on the form. The content of the above-mentioned conjugated long-chain highly unsaturated fatty acid, ester or metal salt of the fatty acid, or other forms in the antitumor agent of the present invention is determined based on the dose (therapeutically effective amount) described later. The dose may be determined in consideration of the number of doses and the daily dose.

The method of administration of the antitumor agent of the present invention includes intravenous injection, subcutaneous injection, parenteral administration using suppositories, ointments and the like, and oral administration using tablets, capsules, powders, granules and the like. . Further, the antitumor agent of the present invention may be used as a mixture with edible oil / fat composition, edible emulsified oil / fat composition, bakery products, cooked food, food and drink such as beverages. Specific examples of such foods and drinks include margarine, shortening, cream, ice cream, butter, cheese, soup, bread, cake, biscuits, crackers,
Examples include, but are not limited to, cookies, jams, and the like. The dose of the antitumor agent of the present invention is a therapeutically effective amount, and cannot be said unconditionally depending on the type of tumor, but generally, for example, in the case of an adult (body weight 60 kg), the conjugated long-chain highly unsaturated fatty acid per day is used. 10-50 as the amount of
00 mg, preferably 20-3000 mg. The antitumor agent of the present invention can be appropriately used in combination with other therapeutic agents including known antitumor agents.

[0016]

The present invention will be described below in detail with reference to examples.

Example 1 300 g of ethylene glycol
And 100 g of potassium hydroxide were placed in a two-liter four-necked flask, and heated to 100 ° C. while blowing nitrogen. Next, 200 g of ethyl eicosapentaenoate was added to the flask, and heated under a nitrogen stream for 2.5 hours. After cooling the reaction solution to room temperature, hydrochloric acid is added to adjust the pH of the reaction solution.
Was adjusted to pH 3, and 50 ml of distilled water was further added thereto to prepare 5
Stirred for minutes. Then, after performing hexane extraction three times,
The hexane solution was washed sequentially with 5% NaCl and distilled water.
Anhydrous sodium sulfate was added to the hexane solution, and after dehydration filtration, hexane was distilled off using a rotary evaporator to obtain conjugated eicosapentaenoic acid. The content of conjugated unsaturated fatty acids in the obtained conjugated eicosapentaenoic acid was determined by UV spectroscopy (Standard Oil and Fat Analysis Test Method 2.
As measured by 4.3.1), the conjugation ratio was 99.1%. The ratio of each ene in all the conjugated double bonds was 51% of conjugated diene, 23% of conjugated triene, 17% of conjugated tetraene, and 9% of conjugated pentaene. Next, using the conjugated eicosapentaenoic acid obtained as described above as a test substance, a cytotoxicity test on tumor cells was performed as follows. The test substance was dissolved in ethanol, and 10
% Of fetal bovine serum and appropriately diluted in RPMI-1640 medium containing 0.1% in each well of a 96-well plastic culture plate.
1 ml each (ethanol concentration in each well was 0.1%
Adjusted to be as follows). Here, 5 × 1
0 ⁴ cells / ml adjusted human colon cancer cells (HT-29)
Was dispensed in 0.1 ml portions, and then cultured at 37 ° C. for 48 hours in a carbon dioxide gas incubator. After the culture, 2,3-bis [2-methoxy-4-nitro-5-sulfo-phenyl] -2H-tetrazolium-
1 μl each of 5-carboxyanilide (50 mg / ml) and phenazine methosulfate (1.5 mg / ml) was added, and the absorbance was measured with a microplate reader. The absorbance of human colon cancer cells cultured in a medium containing no conjugated eicosapentaenoic acid (test substance) was similarly measured, and the growth inhibition rate of human colon cancer cells was calculated according to the following equation. Growth inhibition rate (%) = (1−A / B) × 100 A: Absorbance of cells cultured in medium to which test substance was added B: Absorbance of cells cultured in medium to which test substance was not added The results are shown in Table 1 below. Shown in

Examples 2 and 3 Conjugated docosahexaenoic acid and conjugated arachidonic acid were obtained according to the production method of Example 1. The conjugation ratio and the ratio of each ene in the total conjugated double bond were as follows. (Conjugated docosahexaenoic acid) Conjugation rate; 99% Conjugated diene; 51% Conjugated triene: 18% Conjugated tetraene: 18% Conjugated pentaene: 13% Conjugated arachidonic acid Conjugation rate: 97% Conjugated Diene: 66% Conjugated triene; 22% Conjugated tetraene: 12% Same as Example 1 except that the above conjugated docosahexaenoic acid (Example 2) and conjugated arachidonic acid (Example 3) were used as test substances. , Cytotoxicity test, respectively,
The growth inhibition rate of the cells was determined. The results are shown in Table 1 below.

[Examples 4 to 6] The human colon cancer cells (HT-29 cells) of Example 1 were replaced with human breast cancer cells (MCF-7 cells), and the conjugated eicosapentaenoic acid obtained in Example 1 ( Example 4) In the same manner as in Example 1 except that the conjugated docosahexaenoic acid obtained in Example 2 (Example 5) and the conjugated arachidonic acid obtained in Example 3 (Example 6) were used as test substances. Then, cytotoxicity tests were respectively performed to determine the cell growth inhibition rate. The results are shown in Table 2 below.

Comparative Examples 1 to 5 Eicosapentaenoic acid (Comparative Example 1), docosahexaenoic acid (Comparative Example 2), arachidonic acid (Comparative Example 3), linolenic acid (Comparative Example 4) and conjugated linoleic acid (Comparative Example 5) ) Was used as a test substance, and a cytotoxicity test was performed in the same manner as in Example 1 to determine the cell growth inhibition rate. The results are shown in Table 1 below.

[Comparative Examples 6 to 9] The human colon cancer cells (HT-29 cells) of Example 1 were replaced with human breast cancer cells (MCF-7 cells), and eicosapentaenoic acid (Comparative Example 6) was used.
Cytotoxicity tests were carried out in the same manner as in Example 1 except that docosahexaenoic acid (Comparative Example 7), linolenic acid (Comparative Example 8) and conjugated linoleic acid (Comparative Example 9) were used as test substances. The rejection was determined. The results are shown in Table 2 below.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

The antitumor agent of the present invention has excellent antitumor activity and is highly safe and has few side effects.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) A61K 31/232 A61K 31/23 602

Claims (6)

[Claims] 1. An antitumor agent comprising, as an active ingredient, a fatty acid having a conjugated double bond and having 20 or more carbon atoms, or an ester or metal salt of the fatty acid or another pharmacologically acceptable form. 2. The antitumor agent according to claim 1, wherein the fatty acid contains 40 to 70% of a conjugated diene and 60 to 30% of a conjugated polyene of at least triene in all conjugated double bonds. 3. The fatty acid according to claim 1, wherein the fatty acid is one or more fatty acids selected from the group consisting of conjugated arachidonic acid, conjugated eicosapentaenoic acid, conjugated docosahexaenoic acid, and conjugated docosapentaenoic acid. Antitumor agent. 4. The ester of the fatty acid is an ester of the fatty acid with one or more alcohols selected from the group consisting of alcohols having 1 to 10 carbon atoms, ethylene glycol, propylene glycol and glycerin. The antitumor agent according to any one of claims 1 to 3. 5. The metal salt of the fatty acid is a sodium salt,
The antitumor agent according to any one of claims 1 to 3, which is one or more salts selected from the group consisting of a potassium salt, a calcium salt, a zinc salt and a magnesium salt. 6. A food or drink comprising the antitumor agent according to claim 1.